Glaze composition and antifouling ceramic ware

Abstract

A glaze composition can be used to provide a glaze layer having excellent antifouling performance and visual beauty. The glaze composition contains a glaze forming material, which has a composition determined such that a baked product obtained by baking the glaze composition comprises 55.0 to 67.0 wt % of SiO 2 ; 8.0 to 11.0 wt % of Al 2 O 3 ; 2.0 to 8.0 wt % of SnO 2 ; 15.0 to 21.0 wt % of a divalent metal oxide; and 4.0 to 6.0 wt % of a monovalent metal oxide, with respect to a total weight of the baked product. When a glaze layer is formed by use of this glaze composition, it resists contamination. Even when a dirt deposits on the glaze layer, the dirt can be easily removed from the glaze layer. In addition, the glaze composition can provide a beautiful semi-opaque glaze layer with luster and a reduction in pore generation amount.

1. A glaze composition containing a glaze forming material, wherein a median diameter after grinding and mixing of said glaze forming material is within a range of 4 to 5 μm, and upon baking, said glaze forming material forming a baked product comprising constituents:
 (a) 55.0 to 67.0 wt % of SiO 2 ; 
 (b) 8.0 to 11.0 wt % of Al 2 O 3 ; 
 (c) 2.0 to 8.0 wt % of SnO 2 ; 
 (d) 15.0 to 21.0 wt % of a divalent metal oxide; and 
 (e) 4.0 to 6.0 wt % of a monovalent metal oxide; 
 with respect to a total weight of said baked product. 
 
     
     
       2. The glaze composition as set forth in  claim 1 , wherein said glaze forming material comprises, with respect to a total weight of said glaze forming material,
 (a) 63.0 to 67.0 wt % of SiO 2 ; 
 (b) 8.0 to 10.0 wt % of Al 2 O 3 ; 
 (c) 2.0 to 4.0 wt % of SnO 2 ; 
 (d) 16.0 to 20.0 wt % of a divalent metal oxide; and 
 (e) 4.0 to 6.0 wt % of a monovalent metal oxide. 
 
     
     
       3. The glaze composition as set forth in  claim 1 , wherein the constituent (d) comprises, with respect to the total weight of said glaze forming material,
 (d1) 10.0 to 12.0 wt % of CaO conversion; and 
 (d2) 5.0 to 8.0 wt % of ZnO. 
 
     
     
       4. The glaze composition as set forth in  claim 3 , wherein the constituent (d) comprises (d3) 1.0 wt % or less of MgO, with respect to the total weight of said glaze forming material. 
     
     
       5. The glaze composition as set forth in  claim 1 , wherein said monovalent metal oxide (e) comprises, with respect to the total weight of said glaze forming material,
 (e1) 1.0 wt % or more of Na 2 O; and 
 (e2) 1.0 wt % or more of K 2 O. 
 
     
     
       6. The glaze composition as set forth in  claim 1 , wherein said glaze forming material contains a frit, which is obtained by vitrifying a material containing at least one of the constituents (a) to (e) and grinding the vitrified material. 
     
     
       7. The glaze composition as set forth in  claim 1 , wherein a material containing the constituent (a) of said glaze forming material is a powder having a particle size of 30 pm or less. 
     
     
       8. The glaze composition as set forth in  claim 1 , wherein a material containing the constituent (c) of said glaze forming material is a powder having a median diameter of 0.2 to 4.0 μm. 
     
     
       9. The glaze composition as set forth in  claim 1 , wherein said glaze forming material is prepared by grinding a material containing at least one of the constituents (a) and (c) to obtain a powder or a slurry, then mixing materials containing the remaining constituents with said powder or said slurry, and grinding a resultant-mixture to obtain a powder of said glaze forming material having a required particle size or a slurry thereof. 
     
     
       10. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding a material containing the constituent (a) to obtain a powder having a median diameter of 5 μm or less or a slurry thereof, then mixing materials containing the remaining constituents (b) to (e) with said powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a required particle size or a slurry thereof. 
     
     
       11. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding a material containing the constituent (c) to obtain a powder having a median diameter of 1.5 to 2 μm or a slurry thereof, then mixing materials containing the remaining constituents (a), (b), (d) and (e) with said powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a required particle size or a slurry thereof. 
     
     
       12. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding materials containing the constituents (a) and (c) to obtain a mixed powder having a median diameter of 5 μm or less or a slurry thereof, then mixing materials containing the remaining constituents (b), (d) and (e) with said mixed powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a required particle size or a slurry thereof. 
     
     
       13. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding a material containing the constituent (a) to obtain a powder having a median diameter of 5 μm or less or a slurry thereof, then mixing materials containing the remaining constituents (b) to (e) with said powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a median diameter of 4 to 5 μm or a slurry thereof. 
     
     
       14. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding a material containing the constituent (c) to obtain a powder having a median diameter of 1.5 to 2 μm or a slurry thereof, then mixing materials containing the remaining constituents (a), (b), (d) and (e) with said powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a median diameter of 4 to 5 μm or a slurry thereof. 
     
     
       15. The glaze composition as set forth in  claim 9 , wherein said glaze forming material is prepared by grinding materials containing the constituents (a) and (c) to obtain a mixed powder having a median diameter of 5 μm or less or a slurry thereof, then mixing materials containing the remaining constituents (b), (d) and (e) with said mixed powder or said slurry, and grinding a resultant mixture to obtain a powder of said glaze forming material having a median diameter of 4 to 5 μm or a slurry thereof. 
     
     
       16. The glaze composition as set forth in  claim 1 , wherein the materials containing the constituents of said glaze forming material are ground by means of ball milling using alumina balls. 
     
     
       17. The glaze composition as set forth in  claim 1 , wherein materials containing the constituents of said glaze forming material are ground by means of ball milling using a pot with an alumina liner and alumina balls. 
     
     
       18. The glaze composition as set forth in  claim 1 , comprising a pigment. 
     
     
       19. An antifouling ceramic ware produced by forming a layer of said glaze composition as set forth in  claim 1  on a dried base surface of a raw ceramic ware, and baking said layer at a temperature of 1150 to 1250° C. for 8 hours or more to obtain a glaze layer on a baked base surface of the ceramic ware. 
     
     
       20. The antifouling ceramic ware as set forth in  claim 19 , wherein an X-ray diffraction profile of said glaze layer has only diffraction peaks resulting from SnO 2  crystal. 
     
     
       21. The antifouling ceramic ware as set forth in  claim 19 , wherein an X-ray diffraction profile of said glaze layer has only diffraction peaks resulting from CaSnSiO 5  crystal. 
     
     
       22. The antifouling ceramic ware as set forth in  claim 19 , wherein an X-ray ray diffraction profile of said glaze layer has only diffraction peaks resulting from crystals of SnO 2  and CaSnSiO 5 . 
     
     
       23. The antifouling ceramic ware as set forth in  claim 19 , wherein a thickness of said glaze layer is within a range of 0.2 to 1.2 mm.